"I will cast my vote in support of the Senate tax reform bill. As revised, this bill will provide much-needed tax relief and simplification for lower- and middle-income families, while spurring the creation of good jobs and greater economic growth," Collins said in a statement.

Collins had voiced concerns about a provision in the tax plan that would repeal ObamaCare's individual mandate. The Congressional Budget Office (CBO) said earlier this month that repealing the individual mandate would result in an additional 13 million people becoming uninsured by 2027.

But CBO Director Keith Hall said in a letter sent to Murray on Wednesday that her legislation with Alexander would do little to make up for premium increases or coverage losses if the mandate is repealed.